Free radical monochlorination of 2-methylbutane is carried out at room temperature. Take the relative reactivities per hydrogen for 1 deg : 2 deg : 3 deg C-H as 1 : 3.8 : 5.0. The percentage of 2-chloro-2-methylbutane in the mixture of all constitutional monochloro products is (answer to one decimal place).

JEE Main levelNumerical answerDifficulty 2 of 3g3132

Free radical monochlorination of 2-methylbutane is carried out at room temperature. Take the relative reactivities per hydrogen for $1^{\circ} : 2^{\circ} : 3^{\circ}$ C-H as $1 : 3.8 : 5.0$ . The percentage of 2-chloro-2-methylbutane in the mixture of all constitutional monochloro products is (answer to one decimal place).

Numerical answer type, tolerance 0.2.

2-Methylbutane has 9 primary H (two

CH X_{3}

on C2 and the C4

CH X_{3}

), 2 secondary H (C3) and 1 tertiary H (C2). Relative yields are

9 \times 1 = 9.0

2 \times 3.8 = 7.6

and

1 \times 5.0 = 5.0

, total

21.6

. The tertiary chloride is

5.0/21.6 \times 100 = 23.1

per cent.